How To

An Alternative to Underpinning

Is there any alternative to underpinning adjacent structures when constructing a large building with deep foundations?

A modern alternative, first used in Italy and now being used to a considerable extent in this country, is the slurry wall method. In this method a shallow trench is dug in the configuration of the foundation. This is filled with bentonite slurry to prevent caving or filling with water while excavation continues. Reinforcing steel cages are set in the slurry and the trench is concreted by tremie. Further details may be found in the four-page article
"Slurry Wall Construction," in Concrete Construction, March 1973, page 90.